Scientists have published an analysis of a meteorite fragment collected after an asteroid nearly collided with Earth in 2008. They show that the parent asteroid was huge and the results suggest that a special type of asteroid that maintains the water may be larger and have different mineral compositions than previously thought.
The conclusions of the study were published this week in the journal Nature Astronomy and analyze the chemical composition of a fragment of these meteorite fragments.
The history of the fragments begins in October 2008, when scientists became aware of an asteroid in a course of collision with Earth. They knew that most of the rock would burn as it entered the Earth’s atmosphere and that the remains, if any, would fall into the sands of the wind in the Nubian desert. It provided a unique opportunity for an international team of researchers, including NASA scientists, to predict the arrival of the rocks and then comb the sands for any surviving fragments.
Although the asteroid was relatively small (only about nine tons), its debris was tiny; less than 8.8 pounds (4 kilograms) of meteorites were collected from the desert. Collectively they were christened Almahata Sitta, after a nearby train station. It was the first time an asteroid was detected and then its meteorite debris was collected.
G / O Media may receive a commission
Since its recovery, different pieces of Almahata Sitta have been analyzed, revealing information about the origins and chemical compositions of different parts of the asteroid. The meteorite sample the team studied–nicknamed AhS 202: it was so small that it could fit 10 copies in a nail head, but it came from a gargantuan space rock, a point of origin that precedes the union of the fragment with the rock mass of Almahata Sitta. The team used infrared and X-ray light to study the sample. They found that the fragment was a carbonaceous chondrite, a type of meteorite that formed during the early days of the solar system and may have brought water to Earth, leading to … all of this. In general, carbonaceous chondrites were not thought to have come from parent bodies (asteroids of origin) more than 100 kilometers in diameter.
But researchers found tremolite in its fragment, a mineral that requires an immense amount of pressure to form. The existence of Tremolite in the sample suggests that the diameter of the source asteroid is in the range of 398 over 1,119 miles (640 over 1,800 kilometers), putting it in the wheelhouse of Ceres, the largest object—a dwarf planet, in fact“In the asteroid belt.”
“This is proof for a very large parent body that we didn’t know existed before,” said Vicky Hamilton, a scientist at the Southwest Research Institute and lead author of the recent article, noting the first known presence of tremolite in a carbonaceous chondrite. “The fact that we don’t have other evidence in our meteorite collections helps us confirm what we already suspected, which is that the meteorites we manage to find on Earth are a skewed sample.”
As asteroids exit through space, they will be forced to come into contact with other bodies. These conglomerates of metals and minerals come together and break as their trajectory continues. When a meteorite is on Earth, it’s a compendium of space stories that come together, and the only way to read it is to do a lot of analysis.
“You may have a group of scientists looking at a piece of meteorite and another group looking at another piece of the same meteorite and you will see two different parts of the history of the solar system,” Hamilton said.
That’s how the crack of Hamilton could talk about some origins of a massive asteroid, while another piece of Almahata Sitta could hint punctual existence of a protoplanet. The electroscopy work recently done by the team is a kind of reverse engineering, ranging from what looks like a typical space rock to its specific history, in this case its reference to a massive parent asteroid. It’s like finding a crumb on the kitchen counter — it could be anywhere — but looking at it chemically can tell you the temperature and pressure conditions that caused it and whether that crumb really came from toast this morning or from last week’s birthday cake. .
Although much rarer than other types of asteroids, new information about carbonaceous chondrites could fall from the sky at any time. It’s just a matter of whether meteorologists are vigilant — or lucky — to detect them.